понедельник, 18 марта 2019 г.

Energy loss gives unexpected insights in evolution of quasar jets



 The radio jet of the quasar 4C+19.44, powered by a supermassive black hole lying in the center of its host galaxy and shining at long radio wavelengths as seen by the LOFAR radio telescope (magenta). The background image shows neighboring galaxies in the visible light highlighted thanks to the Hubble Space Telescope (cyan and orange) having the radio jet passing into the dark voids of intergalactic space (Harris et al. 2019). Image Credit: NASA/HST/LOFAR; Courtesy of J. DePasquale



An international team of astrophysicists observed for the first time that the jet of a quasar is less powerful on long radio wavelengths than earlier predicted. This discovery gives new insights in the evolution of quasar jets. They made this observation using the international Low Frequency Array (LOFAR) telescope, that produced high resolution radio images of quasar 4C+19.44 located over 5 billion light-years from Earth. 

 

Supermassive black holes, many millions of times more massive than our Sun reside in the central regions of galaxies. They grow even larger by attracting and consuming nearby gas and dust. If they consume material rapidly, the infalling matter shines brightly and the source is known as a quasar.


Some of this infalling matter is not digested, but instead is ejected in the form of so-called jets that punch through the surrounding galaxy and into intergalactic space for millions of light years. These jets, shining brightly at radio wavelengths, are composed of particles accelerated up to nearly the speed of light, but exactly how these particles achieve energies not attainable on the Earth is yet to be completely solved.


The discovery on quasar 4C+19.44 gives new insights to the balance between the energy in the field surrounding the quasar and that residing in the quasar jet. This finding indicates to an intrinsic property of the source rather than due to absorption effects. It implies that the energy budget available to accelerate particles and the balance between energy stored in particles and in the magnetic field, is less than expected.


“This is an important discovery that will be used for the years to come to improve simulations of jets. We observed for the first time a new signature of particle acceleration in the power emitted of quasar jets at long radio wavelengths. An unexpected behaviour that changes our interpretation on their evolution.” Said Prof. Francesco Massaro from University of Turin. “We knew that this was already discovered in other cosmic sources but it was never before observed in quasars.”


The international team of astrophysicists had observed the jet of the quasar 4C+19.44 at short radio wavelengths, in visible light, and X-ray wavelengths. The addition of the LOFAR images allowed astrophysicists to make this discovery. LOFAR is the first radio facility operating at long radio wavelengths, which produces sharp images with a resolution similar to that of the Hubble Space Telescope.


“We have been able to perform this experiment thanks to the highest resolution ever achieved at these long radio wavelengths, made possible by LOFAR.” Said Dr Adam Deller, an astrophysicist of the Swinburne University of Technology who contributed to the LOFAR data analysis and imaging of 4C +19.44 while at ASTRON in the Netherlands, heart of the LOFAR collaboration.


Dr Raymond Oonk, an astronomer at ASTRON and Leiden University and Dr Javier Moldon, astronomer at the University of Manchester, explained that “We have developed new calibration techniques for LOFAR and this has allowed us to separate compact radio structures in the quasar jet known as radio knots, and measure their emitted light. This result was unexpected and demands to future deeper investigations. New insights and clues on particle acceleration will come soon thanks to the international stations of LOFAR.”


The observation performed on the radio jet of 4C+19.44 was designed by Dr D. E. Harris, supervisor of Prof. Francesco Massaro, while working at the Harvard-Smithsonian Center for Astrophysics, several years ago. He performed the observation in collaboration with Dr Raffaella Morganti and his friends and colleagues at ASTRON. He only got the opportunity to see preliminary results as he passed away on 2015 December 6th. This publication, published in the first March issue of the Astrophysical Journal, is in memory of a career spanned much of the history of radio astronomy.





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Brain Waves When you’re staring into space, you may not…


Brain Waves


When you’re staring into space, you may not think that there is much going on upstairs. In reality, functional MRI has shown us that brain areas are always communicating with each other, even at rest. These coordinated patterns of activity could also be hiding clues about how we function as individuals. For example, there’s less coordinated brain activity at rest in people with autism (fewer red clusters in the bottom row) compared to individuals without autism (top). Neuroscientists have recently gone one step further to show that as symptoms of the disorder become more severe, including intellectual difficulties and repetitive behaviours, this activity in key brain areas is even less coordinated. If neural patterns are related to or even causing the complex behavioural symptoms we see in individuals with autism, in future we may be able to treat the disorder by looking at how to change such patterns.


Written by Gaëlle Coullon



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What is Polymineralic Rock?…


What is Polymineralic Rock? http://www.geologypage.com/2019/03/what-is-polymineralic-rock.html


What is Monomineralic Rock?…


What is Monomineralic Rock? http://www.geologypage.com/2019/03/what-is-monomineralic-rock.html


2019 March 18 Horsehead and Orion Nebulas Image Credit &…


2019 March 18


Horsehead and Orion Nebulas
Image Credit & Copyright: Mario Zauner


Explanation: The dark Horsehead Nebula and the glowing Orion Nebula are contrasting cosmic vistas. Adrift 1,500 light-years away in one of the night sky’s most recognizable constellations, they appear in opposite corners of the above stunning two-panel mosaic. The familiar Horsehead nebula appears as a dark cloud on the lower left, a small silhouette notched against the glow of hydrogen (alpha) gas, here tinted orange. Alnitak is the easternmost star in Orion’s belt and can be found to the left of the Horsehead. Below Alnitak is the Flame Nebula, with clouds of bright emission and dramatic dark dust lanes. The magnificent emission region, the Orion Nebula (aka M42), lies at the upper right, surrounded by the blue glow of reflecting dust. Immediately to its left is a prominent reflection nebula sometimes called the Running Man. Pervasive tendrils of glowing hydrogen gas are easily traced throughout the region.


∞ Source: apod.nasa.gov/apod/ap190318.html


Thank Earth’s magnetic field for water that gives you life

A study by scientists at ANU on the magnetic fields of planets has found that most planets discovered in other solar systems are unlikely to be as hospitable to life as Earth.











Thank Earth’s magnetic field for water that gives you life
This artist’s concept depicts Kepler-186f, the first validated Earth-size planet to orbit a distant star
in the so-called habitable zone [Credit: NASA/Ames/SETI Institute/JPL-Caltech]

Plants and animals would not survive without water on Earth. The sheer strength of Earth’s magnetic field helps to maintain liquid water on our blue planet’s surface, thereby making it possible for life to thrive.


Scientists from the ANU Research School of Astronomy and Astrophysics modelled the magnetic fields of exoplanets – planets beyond our solar system – and found very few have a magnetic field as strong as Earth.


They contend that techniques for finding exoplanets the size of Earth are more likely to find slowly rotating planets locked to their host star in the same way the Moon is locked to Earth, with the same side always facing their host star.


The lead author of the study, PhD scholar Sarah McIntyre, said strong magnetic fields may be necessary to keep wet rocky exoplanets habitable.


“Magnetic fields appear to play an essential role in making planets habitable, so I wanted to find out how Earth’s magnetic field compared to those of other potentially habitable planets,” she said.


Ms McIntyre said Earth’s strong magnetic field had probably played an important role in protecting the atmosphere from the solar wind and keeping the planet wet and habitable.


“Venus and Mars have negligible magnetic fields and do not support life, while Earth’s magnetic field is relatively strong and does,” she said.


“We find most detected exoplanets have very weak magnetic fields, so this is an important factor when searching for potentially habitable planets.”


Associate Professor Charley Lineweaver, a co-author, said scientists had detected hundreds of rocky exoplanets during the past decade.


“Do any of these planets have water on their surfaces? Do they harbor life?” Associate Professor Lineweaver said.


“To help answer these questions, we decided to model their magnetic fields. Strong magnetic fields could protect and preserve a wet surface in a way that weak fields cannot.”


Co-researcher Associate Professor Michael Ireland said finding planets with strong magnetic fields was critical to the search for life elsewhere in the Universe.


“Finding and characterising planets most likely to be wet and temperate will require ambitious yet feasible space missions,” he said.


The study is published online in the journal Monthly Notices of the Royal Astronomical Society.


Source: Australian National University [March 14, 2019]



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ESO’s Cosmic Gems Programme captures the Cosmic Bat’s dusty clouds

Hidden in one of the darkest corners of the Orion constellation, this Cosmic Bat is spreading its hazy wings through interstellar space two thousand light-years away. It is illuminated by the young stars nestled in its core — despite being shrouded by opaque clouds of dust, their bright rays still illuminate the nebula. Too dim to be discerned by the naked eye, NGC 1788 reveals its soft colours to ESO’s Very Large Telescope in this image—the most detailed to date.











ESO's Cosmic Gems Programme captures the Cosmic Bat's dusty clouds
Hidden in one of the darkest corners of the Orion constellation, this Cosmic Bat is spreading its hazy wings through
interstellar space two thousand light-years away. It is illuminated by the young stars nestled in its core – despite
being shrouded by opaque clouds of dust, their bright rays still illuminate the nebula. Too dim to be discerned
 by the naked eye, NGC 1788 reveals its soft colours to ESO’s Very Large Telescope in this image – the
most detailed to date [Credit: ESO]

ESO’s Very Large Telescope (VLT) has caught a glimpse of an ethereal nebula hidden away in the darkest corners of the constellation of Orion (The Hunter) — NGC 1788, nicknamed the Cosmic Bat. This bat-shaped reflection nebula doesn’t emit light — instead it is illuminated by a cluster of young stars in its core, only dimly visible through the clouds of dust. Scientific instruments have come a long way since NGC 1788 was first described, and this image taken by the VLT is the most detailed portrait of this nebula ever taken.
Even though this ghostly nebula in Orion appears to be isolated from other cosmic objects, astronomers believe that it was shaped by powerful stellar winds from the massive stars beyond it. These streams of scorching plasma are thrown from a star’s upper atmosphere at incredible speeds, shaping the clouds secluding the Cosmic Bat’s nascent stars.


NGC 1788 was first described by the German–British astronomer William Herschel, who included it in a catalogue that later served as the basis for one of the most significant collections of deep-sky objects, the New General Catalogue (NGC).



A nice image of this small and dim nebula had already been captured by the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory, but this newly observed scene leaves it in the proverbial dust. Frozen in flight, the minute details of this Cosmic Bat’s dusty wings were imaged for the twentieth anniversary of one of ESO’s most versatile instruments, the FOcal Reducer and low dispersion Spectrograph 2 (FORS2).


FORS2 is an instrument mounted on Antu, one of the VLT’s 8.2-metre Unit Telescopes at the Paranal Observatory, and its ability to image large areas of the sky in exceptional detail has made it a coveted member of ESO’s fleet of cutting-edge scientific instruments. Since its first light 20 years ago, FORS2 has become known as “the Swiss army knife of instruments”.


This moniker originates from its uniquely broad set of functions. FORS2’s versatility extends beyond purely scientific uses—its ability to capture beautiful high-quality images like this makes it a particularly useful tool for public outreach.


This image was taken as part of ESO’s Cosmic Gems programme, an outreach initiative that uses ESO telescopes to produce images of interesting, intriguing or visually attractive objects for the purposes of education and public outreach. The programme makes use of telescope time that cannot be used for science observations, and — with the help of FORS2 — produces breathtaking images of some of the most striking objects in the night sky, such as this intricate reflection nebula. In case the data collected could be useful for future scientific purposes, these observations are saved and made available to astronomers through the ESO Science Archive.


Source: ESO [March 14, 2019]




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Research project to investigate impact of extreme weather on biodiversity and pollinating...

Markus Franzén, doctor in ecology at the department of biology and environmental science at Linnaeus University, has been granted SEK 3 million by Formas for his research project, “Cascading effects of drought on farming/grazing and farmland biodiversity.”











Research project to investigate impact of extreme weather on biodiversity and pollinating insects
Credit: Liv Ravnböl

The drought in Sweden during the summer of 2018 led to acute food shortage for livestock and became a hot topic in the news. Together with Anders Forsman, professor of evolutionary ecology, Markus Franzén has been granted research funds to study how extreme drought and grazing impact plant and animal life in grasslands.
Insects are important pollinators, and butterflies have been shown to be good indicators of species diversity and the condition of the environment. In this project the researchers will focus on the marsh fritillary, a flower-visiting butterfly, and its host plant Succisa pratensis. The study will be performed on the island of Gotland in the Baltic Sea, an area where the drought was particularly severe in 2018.


“Our hypothesis is that the drought resulted in food shortages for parts of the biodiversity and for livestock in our open farmlands, which in its turn has led to intensified grazing over larger areas”, says Markus Franzén.











Research project to investigate impact of extreme weather on biodiversity and pollinating insects
Credit: Liv Ravnböl

In the long term, the combined effect of drought and extensive grazing can lead to an ecosystem collapse, which has consequences also for agricultural production of crops, meat, milk, etc. Meadows and pastures are home to many different species of plants and animals that depend on livestock.
Grazing is positive for biodiversity because it keeps the landscape open and dominant plants are limited in their distribution. Too intense grazing, however, can be devastating, in particular for pollinating insects. During the extreme drought last summer, farmers were given permission to let their livestock graze on more or less all grasslands, which is not good for biodiversity.


“We have seen a very dramatic reduction of important habitats after the drought. In particular the marsh fritillary and other species linked to wet meadows seem to have had their number reduced”, says Franzén.











Research project to investigate impact of extreme weather on biodiversity and pollinating insects
Credit: Liv Ravnböl

It is difficult to predict what will happen in the future. By making use of the increased knowledge about how ecological processes are affected by extreme weather conditions, research can contribute with projections about how biodiversity may respond under different climatic conditions and scenarios.
“Measures that promote insects and their host plants do not necessarily have to be hard to implement. Much can be achieved through relatively small measures; for instance, setting aside land where livestock do not graze extensively. This may allow plants and pollinators to recover”, explains Anders Forsman.


The researchers hope that their study can inform future development of the common agricultural policy and in this way contribute to a sustainable farming production that maintains biodiversity, also during weather conditions like extreme drought.


Authors: Markus Franzén & Liv Ravnböl | Source: Linnaeus University [March 14, 2019]



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Ocean sink for man-made CO2 measured

Not all of the CO2 generated during the combustion of fossil fuels remains in the atmosphere and contributes to global warming. The ocean and the ecosystems on land take up considerable quantities of these man-made CO? emissions from the atmosphere.











Ocean sink for man-made CO2 measured
Using the results of extensive ocean CO2 measurements, we can now estimate how much man-made
CO2 the ocean has taken up in the last few decades [Credit: andrej67/iStock]

The ocean takes up CO2 in two steps: first, the CO2 dissolves in the surface water. Afterwards, the ocean’s overturning circulation distributes it: ocean currents and mixing processes transport the dissolved CO2 from the surface deep into the ocean’s interior, where it accumulates over time.


Carbon sink in the ocean


This overturning circulation is the driving force behind the oceanic sink for CO2. The size of this sink is very important for the atmospheric CO2 levels: without this sink, the concentration of CO2 in our atmosphere and the extent of anthropogenic climate change would be considerably higher.


Determining what share of the man-made CO2 the oceans absorb has long been a priority for climate researchers. An international team of scientists led by Nicolas Gruber, Professor for Environmental Physics at ETH Zurich, has now determined this oceanic sink over a period of 13 years. As reported in the journal Science, the researchers have found that the ocean has taken up from the atmosphere as much as 34 gigatonnes (billions of metric tonnes) of man-made carbon between 1994 and 2007. This figure corresponds to 31 per cent of all anthropogenic CO2 emitted during that time.


The marine sink is intact


This percentage of CO2 taken up by the oceans has remained relatively stable compared to the preceding 200 years, but the absolute quantity has increased substantially. This is because as long as the atmospheric concentration of CO2 rises, the oceanic sink strengthens more or less proportionally: the more CO2 is in the atmosphere, the more is absorbed by the oceans – until it becomes eventually saturated.


So far, that point has not been reached. “Over the examined period, the global ocean continued to take up anthropogenic CO2 at a rate that is congruent with the increase of atmospheric CO2 ,” Gruber explains.


These data-based research findings also confirm various earlier, model-based estimates of the ocean sink for man-made CO2. “This is an important insight, giving us confidence that our approaches have been correct,” Gruber adds. The results further allow the researchers to draw conclusions about the CO2 sink of the ecosystems on land, which are more difficult to determine.


Regional differences in the absorption rate


While the overall results suggest an intact ocean sink for man-made CO2, the researchers also discovered in the different ocean basins considerable deviations from the uptake expected from the rise in atmospheric CO2. The North Atlantic Ocean, for instance, absorbed 20 per cent less CO2 than expected between 1994 and 2007.


“This is probably due to the slowdown of the North Atlantic Meridional Overturning Circulation in the late 1990s, which itself is most likely a consequence of climate variability,” Gruber explains. But this lower sink in the North Atlantic was offset by a considerably greater uptake in the South Atlantic, such that the uptake by the entire Atlantic developed as expected.


The researchers documented similar fluctuations in the Southern Ocean, in the Pacific and in the Indian Ocean. Gruber emphasises: “We learned that the marine sink does not just respond to the increase in atmospheric CO2. Its substantial sensitivity to climate variations suggests a significant potential for feedbacks with the ongoing change in climate.”


Results of two surveys


The results are based on a global survey of CO2 and other chemical and physical properties in the various oceans, measured from the surface down to depths of up to 6 kilometres. Scientists from 7 countries participated in the internationally coordinated programme that started in 2003. Globally they carried out more than 50 research cruises up to 2013, which were then synthesized into a global data product.


For their analyses, the researchers used a new statistical method developed by Gruber and his former Ph.D. student, Dominic Clement. This method allowed them to distinguish between the changes in the man-made and the natural CO2 components that make up the changes in the total concentration of dissolved CO2 in the water. Natural CO2 refers to the amount of CO2 that existed in the oceans prior to industrialisation.


Gruber had already participated in a similar study around the turn of the millennium. Using observations obtained from the very first global CO2 survey conducted between the late 1980s and the mid-1990s, that study estimated that the ocean had taken up around 118 gigatonnes of carbon from the beginning of industrialisation around 1800 until 1994. His current team of researchers extended this analysis up to 2007, permitting them not only to establish the budget for man-made CO2 for the 1994 through 2007 period, but also to assess the intactness of the ocean carbon sink.


Increasing CO2 content acidifies marine habitats


By moderating the rate of global warming, the oceanic sink for man-made CO2 provides an important service for humanity, but it has its price: the CO2 dissolved in the ocean acidifies the water. “Our data has shown that this acidification reaches deep into the ocean’s interior, extending in part to depths of more than 3000 m,” Gruber says.


This can have serious consequences for many marine organisms. Calcium carbonate spontaneously dissolves in acidified environments, which poses a hazard to mussels and corals whose shells and skeletons are made of calcium carbonate.


The changing chemical composition of the ocean can also impact physiological processes such as the breathing of fish. Gruber is convinced: “Documenting the chemical changes imparted on the ocean as a result of human activity is crucial, not least to understand the impact of these changes on marine life.”


Author: Michael Keller | Source: ETH Zurich [March 14, 2019]



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Sources and Sinks: Tectonics trigger Earth’s ice ages

For the entire history of our species, humans have lived on a planet capped by a chunk of ice at each pole. But Earth has been ice-free for about 75 percent of the time since complex life first appeared. This variation in background climate, between partly glaciated and ice-free, has puzzled geologists for decades.











Sources and Sinks: Tectonics trigger Earth's ice ages
Over the last 540 million years, as the Earth’s tectonic plates have shifted, researchers have found that periods of major
tectonic activity (orange lines) in the tropics (green belt) were likely triggers for ice ages during those same periods
[Credit: MIT]

Now a team of scientists led by UC Santa Barbara’s Francis Macdonald has published a study suggesting that tectonic activity may be the culprit. They found that long-term trends in Earth’s climate are set by the presence or absence of collisions between volcanic arcs and continents in the tropics. The results appear in the journal Science.


“There’ve been a few hypotheses but no agreements as to why we have warmer or colder climates on these very long timescales,” said Macdonald, a professor in the Department of Earth Science.


And when Macdonald says “long timescales,” he’s talking about 10 million-year periods, at a minimum. These are broad climatic trends, the backdrop against which natural and human-made fluctuations play out. Scientists have a relatively good understanding of what factors influence the climate on a thousand-year timescale, according to Macdonald.


On any scale, though, the primary agent of climate change is carbon dioxide (CO2). The question is what factors influence the amount of CO2 in atmosphere. Some processes produce CO2, while others absorb it. Scientists call these sources and sinks.


The debate among geologists is whether sources or sinks affect the climate more. “Some have argued that CO2 sources, like volcanism, have driven climate change on long timescales, while others have argued that, no, it’s the sinks that have caused climate change on these timescales,” said Macdonald.


He believes it’s mostly the sinks, specifically vast deposits of rock that absorb CO2 through chemical reactions. But these carbon sinks are not distributed evenly across the surface. For instance, greater Indonesia is only 1-2 percent of the Earth’s exposed land area, but accounts for roughly 10 percent of the current geologic carbon sink.











Sources and Sinks: Tectonics trigger Earth's ice ages
The dense ocean crust melts as it slides under the continent, fueling a volcanic arc
[Credit: Domdomegg]

The activity of these sinks depends on a number of factors. Water is important for the chemical reactions and also washes the end results away into the oceans, where they consume CO2. Mountain-building increases the reactions by uplifting and exposing new rock. In flat terrain, the soil shields the underlying rock.


Rock type also plays a key role. Stone rich in iron and magnesium has simpler chemical bonds that are more easily broken down. This makes these mafic rocks, like basalt, better carbon sinks than rocks such as granite, which have more complex bonds.


Plate tectonics is what drives this geologic carbon cycle. When one tectonic plate slides under another — usually a dense ocean plate under a continent — the melting rock fuels a row of volcanoes on the top plate called a volcanic arc. The Cascade Range of the Pacific Northwest is one example of this.


Macdonald and his colleagues reckoned that when these volcanic arcs collide with another continent, the collision uplifts mafic rocks. These rocks are readily eroded, particularly in warm, wet, tropical latitudes, and the sediment is sent out to oceans where it consumes CO2. So, he reasoned, when these collisions happen in the tropics, they drive the climate toward cooling.


“The tropics are where the rocks weather best because it’s the warmest and wettest,” explained coauthor Lorraine Lisiecki, an associate professor also in UC Santa Barbara’s Department of Earth Science.


To test their hypothesis, the team used reconstructions of the continents and mountain-building events that scientists had built up over the past decades. This gave them an idea where and when arc-continent collisions happened. They limited themselves to the last 500 million years, since the geologic record is much less complete, and reconstructions less certain, before that time.











Sources and Sinks: Tectonics trigger Earth's ice ages
The extent of polar ice (blue) varies with the amount of arc-continent collisions (orange)
that occur in the tropics (green) [Credit: Francis MacDonald]

Temperature is harder to get a read on than geography, so the team used a simple metric: Was there ice on the poles at a given time or not? They reconstructed this information from the literature by looking at data on rocks that form only in the presence of ice. What they found was that Earth had significant ice cover during only four periods in their time window.


Combining the geographic and temperature data, the team found that over the last 500 million years, glacial climates occurred during periods of extensive collision between continents and volcanic arcs in the tropics. There was less than a 1 percent probability that the match was due to chance.


“Given how many things are changing on Earth at the same time, it’s amazing that it all came out really clean and matched so well,” said Lisiecki.


The collisions have the added effect of shutting down volcanic arc activity, which cuts off that source of CO2. “But if it was a volcanic effect, it wouldn’t matter where the volcano was,” Lisiecki said. It’s only the weathering effect where latitude makes a difference. And the team found a much stronger relationship between the climate and collisions that happened in the tropics, rather than those that were outside the tropics.


“These hypotheses are not necessarily entirely independent,” said Macdonald, “but our analysis suggests that the strongest relationship is with the weathering piece.”


Macdonald embarked on this large compilation project after several of his colleagues had pushed back on results from studies with smaller scopes. “I thought, ‘You’re absolutely right. We need to look at this more broadly,'” he recalled. Now the team hopes this paper challenges their colleagues to make a more rigorous case for their own hypotheses.


Macdonald and Lisiecki also know that this paper is not the last word. “The database is open,” Macdonald said, “so I’m hoping that this is an iterative project. And as more constraints come online, they can be entered and the model can be refined.” To that end, he is currently investigating how strong an effect rock type has on this hypothesis.


Humans have lived for hundreds of thousands of years with little concept of the dramatic changes the planet has witnessed over the eons. Although the subjects it studies are ancient, modern geology developed relatively recently. The theory of plate tectonics, for example, was not widely accepted until the 1960s. “We often think of Earth as always being like we’re seeing now,” said Macdonald. “But it’s been a totally different planet throughout its history.”


Author: Harrison Tasoff | Source: University of Santa Barbara, CA [March 14, 2019]



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Open thread: What are the linguistic implications of Olalde et al. 2019?

I was going to write a huge post on the linguistic implications of the latest batch of ancient DNA from Iberia courtesy of Olalde et al. 2019, and then I thought better of it. Admittedly, I don’t know enough about the languages of prehistoric Iberia to say anything really useful on the topic. So instead here’s an open thread to bounce around a few ideas in the comments.
Just briefly, this is what Olalde et al. say in the abstract of their paper about the relationship between ancestry from the Pontic-Caspian steppe and languages in Iron Age Iberia:



We reveal sporadic contacts between Iberia and North Africa by ~2500 BCE and, by ~2000 BCE, the replacement of 40% of Iberia’s ancestry and nearly 100% of its Y-chromosomes by people with Steppe ancestry. We show that, in the Iron Age, Steppe ancestry had spread not only into Indo-European–speaking regions but also into non Indo-European–speaking ones, and we reveal that present-day Basques are best described as a typical Iron Age population without the admixture events that later affected the rest of Iberia.



However, in the paper it’s revealed that “Indo-European regions” actually refers to a Celtic-speaking part of northern Iberia. And it’s quite possible that Celts moved into this area from outside of Iberia only during the Iron Age. In other words, the speakers of Indo-European languages here may not have been the descendants of any of the people with steppe ancestry who came to Iberia by ~2000 BCE.
So I’m probably not alone in thinking that the question of the linguistic affinities of these early migrants with steppe ancestry to Iberia (mostly associated with the Bell Beaker culture or BBC) remains open, especially since they evidently had such a profound genetic impact on the later non Indo-European-speaking populations of southern Iberia. Could they have been the speakers of unattested Indo-European languages, as well as Proto-Iberian and Proto-Basque? If not, why not?
Below is a Principal Component Analysis (PCA) of West Eurasian genetic variation. I highlighted some of the ancient samples from Olalde et al., as well as Basques and other present-day Iberians. The Basques form a tight cluster with most of the Copper, Bronze and Iron Age Iberians, and, unlike the other present-day Iberians, they basically look like an Iberian population from the metal ages. The relevant datasheet is available here.



This is nothing new and very much in line with the results in Olalde et al., but I wanted to emphasize the point that Basques were not just a group that experienced an extreme founder effect in R1b-P312, which is a Beaker-specific Y-chromosome lineage. Rather, they’re still very similar to Iberian Beakers in terms of overall genetic structure. So where did they get their language?
See also…
Late PIE ground zero now obvious; location of PIE homeland still uncertain, but…

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Fluorite | #Geology #GeologyPage #Mneral Locality: Minerva…


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Silver | #Geology #GeologyPage #Mineral Locality: Kongsberg…


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What is Black Quartz?…


What is Black Quartz? http://www.geologypage.com/2019/03/what-is-black-quartz.html


Nine Ladies Stone Circle and Stanton Moor, Derbyshire, 17.3.19.

Nine Ladies Stone Circle and Stanton Moor, Derbyshire, 17.3.19.











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Coming Unstuck Essential constituents of our blood, platelets…


Coming Unstuck


Essential constituents of our blood, platelets reduce bleeding by clumping together, but their tendency to aggregate has a darker side: platelets can form dangerous blood clots, and facilitate the movement of cancerous cells in the bloodstream. Patients at high risk of blood clots are often prescribed anti-platelet medication, yet this leaves them vulnerable to severe bleeding in case of injury or surgery. Scientists are developing a solution based on modified platelets, stripped of many of their components by detergents. These platelet decoys (pictured, coloured pink) lose their ability to stick together, for example no longer becoming enmeshed in the presence of collagen fibres (in grey). Laboratory experiments suggest that treatment with these decoys reduces aggregation in the bloodstream, an effect that can rapidly be reversed by adding more real platelets. While still in early stages of testing, this quick and flexible action would represent a major improvement on existing therapies.


Written by Emmanuelle Briolat



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Arbor Low Neolithic Henge and Stone Circle, Derbyshire, 17.3.19.

Arbor Low Neolithic Henge and Stone Circle, Derbyshire, 17.3.19.












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